“Abolish the IRS” continues to be a reliable applause line at Ted Cruz rallies.

So as Tax Day approaches, it’s worth pondering: What would the country look like without its main revenue collection agency?

Fortunately (or un-), we’re already more than a sixth of the way to finding out.

Over the past six years, for misguided ideological and punitive reasons, Congress has axed the IRS’s budget by 17 percent in inflation-adjusted terms. These draconian cuts, according to new data, have made life more painful for law-abiding taxpayers, have eased it for cheats and may have irreparably harmed our nation’s fiscal health.

Thanks to funding shortfalls, well-meaning taxpayers have endured awful treatment from the IRS. Only 38 percent of people calling the agency with a question last fiscal year ever got through, for example, with the average hold time lasting a half-hour.

Those who did reach an agent were helped only if they had a “basic” question, rather than a complex one (you know, the kind people might not want to rely on Google to address).

The backlog of written correspondence looks even worse. At the end of fiscal 2010, 606,000 taxpayer letters to the agency were sitting unanswered; five years later, the backlog was 937,000.

As our already byzantine tax code has gotten more complicated (thanks to Obamacare, among other things), honest taxpayers need more help navigating it. Yet the IRS is less equipped to help them.

You know who has benefited from the crippling of the IRS? Taxpayers who play fast and loose with the law.

As a result of budget cuts, the IRS has lost about a quarter of its main enforcement workforce since fiscal 2010.

Accordingly, audit rates have plummeted — especially for the mega-corporations that can afford armies of accountants and tax attorneys to grind down what they owe Uncle Sam.

The amount of time revenue agents spent auditing the biggest corporations — those with at least $20 billion in assets — halved between 2010 and 2015, according to a new analysis from Syracuse University’s Transactional Records Access Clearinghouse; the recommended additional taxes resulting from audits of these mega-corporations dropped by close to three-quarters, resulting in billions in lost revenue.

That’s not because Americans suddenly became more law-abiding. The IRS simply doesn’t have the resources to go after people and companies that are paying less than they legally owe.

I realize a lot of Americans will applaud the news that audit rates are down. What these cheerleaders don’t realize is that they’re not the primary beneficiaries of this development.

In fact, they will probably pay dearly.

Cutting back on IRS enforcement effectively means giving a generous break to aggressive tax planners and cheats. Eventually, those revenue losses will have to be offset with higher tax rates on honest people. As more Americans start to feel like chumps for obeying the law, cheating will rise further, forcing statutory tax rates even higher.

We’ve seen this vicious cycle of declining tax compliance and rising rates play out abroad, in cash-strapped countries such as Greece and Italy.

Of course, IRS funding cuts have already hurt the federal budget. Historical collection data suggest that the government is currently losing out on more than $5 billion annually in enforcement revenue, in order to save just a few hundred million dollars on spending for the IRS. If voluntary compliance falls — whether because people become resentful that others aren’t paying their fair share, because they no longer fear getting caught or because they’re annoyed that no one at the IRS will answer the damn phone — that lost revenue will mount.

For these reasons, fiscal conservatives and fans of low tax rates – i.e., Republicans — should be the most enthusiastic advocates of increasing funding for the IRS.

They’re not, of course. One possible reason is that they’re being penny-wise and pound-foolish. Another is lingering rage over the IRS’s 2013 scandal, when it improperly targeted for review conservative groups applying for federal tax-exempt status.

Multiple investigations and reprimands followed, and the agency has implemented nearly all of the recommendations that resulted. Oversight probably needs to increase further. But budget cuts are an ineffective way to force the IRS to do its job better or more efficiently.

“The Veterans Health Administration had problems, OPM had problems, the Secret Service had problems,” IRS Commissioner John Koskinen said in a phone interview last week. The response, he noted, was to “provide appropriate funding to deal with those problems” — not to cut them all off at the knees.